Golf is a game wherein the ideal striking of a golf ball generates a shot which is long and straight. Normally, the driver is the club which accomplishes this task, because it is the club used to hit the golf ball as far as possible.
By generating high club head speed at impact, the flight of the golf ball is prolonged. But, as the club head moves toward impact, air directly effects the club head, and reduces the possibility for the ideal striking of the golf ball.
Aerodynamic effects of golf club heads have been investigated through the years. U.S. Pat. No. 1,541,126 to Dunn attempted to raise the center of gravity of the golf club by forming the golf club head with a concave sole. U.S. Pat. No. 3,166,320 to Onions provides a groove extending across the rear of the club head to reduce bounce. U.S. Pat. No. 4,444,392 to Duclos recognized an aerodynamic drag or vacuum at the rear of the club head and developed an internal cavity in an attempt to eliminate the vacuum. U.S. Pat. No. 4,850,593 to Nelson also recognized the aerodynamic drag near impact and utilized a sole trough to reduce this drag at the top of the swing rather than near impact.
Each of the noted patents have recognized one element effecting the speed of the club head near impact. However, not only is there an aerodynamic drag or vacuum near the rear of the club head, but the air moving around the club head also causes rotational movement of the club head. This rotational movement rotates the club head near impact and thus at impact the face of the club head is either opened or closed. This type of striking causes side spin on the ball. It is well known that a golf ball with side spin does not fly straight. Instead, depending on the amount and direction of spin, the ball will either hook or slice.